1. Field of the Invention
The present invention relates to an electric field sensor, a fabrication method thereof, and a storage unit having the same.
2. Description of the Related Art
Hard disk drives (HDDs) are devices for writing and reading information by using a magnetic read/write head while a recording medium rotates, and are mainly used as main storage units of personal computers (PCs). That is, according to a magnetic recording method, a plurality of magnetic domains, which are magnetized in a first direction and an inverse direction to the first direction (hereinafter, referred to as a ‘second direction’), are generated on a magnetic recording medium using a magnetic field, such that the magnetic domains magnetized in the first direction and the second direction respectively correspond to data ‘0’ and data ‘1’.
The recording density of HDDs employing such magnetic recording method has rapidly increased for recent years, and accordingly, it is expected for HHDs employing a horizontal magnetic recording method to have a recording density of around 100 Gb/in2 and HHDs employing a vertical magnetic recording method to have a recording density of a maximum of 500 Gb/in2. However, since it is difficult to generate a strong local magnetic field with a magnetic read/write head, the increase in recording density is limited.
Recently, researches have been conducted on a ferroelectric recording medium, in which data is recorded by an electric field instead of a magnetic field, and an electric field sensor for reading and writing the data. Such electric field recording method forms electric domains polarized in a first direction and an inverse direction to the first direction (hereinafter, referred to as a ‘second direction’) on the surface of a ferroelectric material using an electric field, where the electric domains polarized in the first direction and the second direction respectively correspond to data ‘0’ and ‘1’. Since a resistance of an electric field sensor located on an electrical domain depends on a polarized direction of the electrical domain, an amperage of a current flowing between a source electrode and a drain electrode of a  electric field sensor differs according to the resistance. Thus, information recorded in the electrical domain can be read by detecting a change in the current. According to the electric field recording and reproducing method, a recording density of more than 1 Tb/in2 can be obtained.
An electric field sensor provides an electric field inducing polarization in a recording medium when recording and detects a change in an electric field induced by a polarization voltage of an electrical domain of the recording medium when reproducing.